Aqueous tint finish



atentcd May H5, 1945 neurons 'rm'r rmrsn Victor L. Denny, Jrn, Augusta County, Va, as-

signor to du Pont de Nemours & Comgton, Del, a corporation of Dela- No Drawing. Application May 6, 1M1,

Sol No. 392,180 I 4 Claims. (Cl. 8-13) "Xhis invention relates to an improved aqueous tint finish and to a method for improving the stability of aqueous tint finishes for filaments, yarns, and threads of organic derivatives of cellulose. More particularly, this invention relates to the finishing and tinting of filaments, yarns, and threads of cellulose acetate with an aqueous tint finish of improved stability, and to the improved tint finish composition.

In the manufacture of organic cellulose derivatlve continuous filament yarn such as cellulose acetate yarn, a finishing composition is usually applied immediately after the filaments are formed and prior to the initial windup of the yarn. The finish is primarily a lubricant to protect and assist the yarn in further textile processing, and generally comprises one or more vegetable, animall, or mineral oils, soaps, and sulionated oil or the like in an aqueous emulsion. For brevity, such an oil-water emulsion will be referred to subsequently as an aqueous finish, and this expression aqueous finish is here defined as a water emulsion of the oils, soaps, and the like heretofore used to lubricate and assist in the further processing of filaments, yarns, and threads of organic cellulose derivatives.

Wrldentification, or other specific observational purposes, a fugitively colored yarn is frequently desired. To impart the desired color to the yarn, various commercial water-soluble dyes, such as Pontacyl Green S. N. Extra (Color Index No. 737), Pontacyl Green N. V. Conc. (Color Index No. 735), Pontacyl Green B (Color Index No. 686), Brilliant Acid Green 63 (Color Index No. 667), Acid Violet '7 B. N. (Color Index No. 701) Pontacyl Fast Violet 10B (Color Index No. 696), Pontacyl Violet C4B (Color Index No. 698), Sulpho Rhodamine B (Color Index No. 748), and Alphazurine F. G. (Color Index 671), are added to the aqueous finish, The resulting tint finishes, while yielding a dyeing of desired fugitivity, are however not entirely satisfactory for the reason that the emulsions are unstable and readily break down so that the finishes cannot be applied to the yarn with the necessary degree of uniformity. Attempts to apply oil-soluble colors from an oil solution, and to apply waterand alcohol-soluble colors from an alcohol solution with a view to avoiding unstabillty of the tint finishes have not been successful because the fugitivity of the color so applied was poor.

An object of this invention therefore is to provide aqueous tint finishes for filaments, yarns, and threads of organic derivatives of cellulose, which finishes are substantially stable. A further object is to stabilize aqueous tint finishes without impairing thefugitivity of the color. A still further object is in the provision of aqueous tint finishes which are substantially stable and which tint filaments, yarns, and threads of cellulose acetate with colors, of desired fugitivlty. These and other objects will more clearly appear hereinafter.

The dyestuffs listed above, and in fact nearly all commercial dyestufis contain one or more inorganic salts, generally sodium chloride, ammonium chloride, sodium sulfate, or ammonium sulfate. Such salts are present in commercial dyestufis as the result of the saltine-out operation and usually additional salts are added as a. diluent in the standardizing process to attain the desired color strength. The salt content of dyestufis will vary from about 5% to I have found that the instability of aqueous tint finishes is due to the presence therein of inorganic salts introduced with the commercial dyestufis used to impart fugitive tints to the yarns of organic cellulose derivatives. My invention therefore resides in the formulation and use of aqueous tint finishes containing in each instance a dyestufi', the inorganic salt content of which has been substantially removed prior to its addition to the finish composition.

Any known method may be employed for treating the commercial dyestufis to separate the coloring matter from the inorganic salts. A convenient and satisfactory extraction of the coloring matter from the dyestufl can be accomplished as follows:

1. Dissolve the coloring matter in a suitable low-boiling solvent wh ch does not appreciably dissolve the salt present in the dyestufi. (The most suitable solvent, the temperature to be used, and the method of dissolving will depend upon the salt and the dyestufl involved; methanol, and by volume ethyl or denatured alcohol have been found generally most satisfactory.)

2. Filter the above solution of the color ingredlent to separate it from the undlssolved salt.

3. Dilute the above filtrate with water or with recovered solvent diluted with water from a previous operation to obtain, after distillation (step 4). a suitable concentration of dye solution.

4. D still, to recover the solvent and leave an essentially salt-free and solvent-free aqueous solution. of the color ingredient of the dyestufi'.

The aqueous solution of the color ingredient of the dyestuff is incorporated directly in a suitable aqueous finish to yield a tint finish of greatly improved stability.

The following examples further illustrate the invention:-

To one of these base finishes 0.7 part of commercial Pontacyl Violet 043 (index No. 698) and 0.8 part of commercial Pontacyl Fast Violet 10B (index No. 696) was incorporated in suiiicient soft water to make the total 100 parts. Commercial Pontacyl Violet C4B contained approximately 18% inorganic salts and commercial Pontacyl Fast Violet 10B contained approximately 33% of inorganic salts, which means that approximately 0.4 part of inorganic salts was added to the finish. Hereinafter, I shall refer to this tint finish as "tint flIl1h A." To another of these base finishes a sufiicient amount of aqueous salt-free solution of dyestuif corresponding in color-strength to 0.8 part of commercial Pontacyl Fast Violet 10B and 0.7 part of commercial Pontacyl Violet C413 was added insufficient soft water to make the total 100 parts. This finish will hereinafter be designated as tint finish B. A third finish was prepared by diluting the remaining base finish with suillcient soft water so as to make the ingredients total 100 parts. This will be termed the "natural finish.

Portions of these three finishes were set aside in separate covered containers for observation on stability. Within twenty-four hours, tint finish A showed adefinite separation of ingredients or poor stability, whereas the natural finish and tint finish B showed no appreciable segregation or break-down even after two weeks of standing.

When these three finishes were used separately for the finishing and/or tinting of cellulose acetate yarn by passing the freshly formed yarn in their travel from dry spinning cells to take-up bobbins in contact with rotating wiper rolls dipping into the finishes contained in troughs, the finishes being applied to the yarns under identical conditions, very uniform application in the finish was obtained by the use of the natural finish and tint finish B, whereas the yarn was non-uniformly finished with tint finish A due to separation of the ingredients therein. The two samples of tinted yarns were equally ingitive but the yarn treated with tint finish B was oi markedly better quality. Inspection showed eight times as much second quality yarn where tint finish A was used as compared with similar yarns treated with tint finish B. Further, yarn treated with tint finish A required the application of additional oil or other lubricating agent after it had-been twisted and as it was being wound into the final package, whereas yarn treated with tint finish B could be twisted and subsequently wound into a final package without necessitating the use of additional oil and to produce higher quality packages or yarn. The following examples illustrate aqueous tint finishes particularly suitable for application to yarns of cellulose acetate: 7

Example 11 An aqueous dispersion of:

Percent 1.5

Soap Mineral oil 3.0 ol n11 1.0

to which add an aqueous salt-free solution of dyestuffs corresponding in color strength to:

- Percent Commercial Pontacyl Fast Violet 103 (index No. 696) Commercial Pontacyl Violet 043 (index No.

Example III to which add an aqueous salt-free solution of dyestufl corresponding in color strength to:

' Percent Commercial Pontacyl Fast Violet 103 (index No. 096) 0.1

Example IV Anaqueous dispersion of:

Percent Soap 1.0 Mineral oil 6.0 Olive oil 2.0

to which add an aqueous salt-free solution of dyestuii corresponding in color strength to:

Percent Commercial Pontacyl Violet 0413 (index No.

The invention is not restricted to the exact ma- ,terials and conditions set out in the foregoing examples but is susceptible rather to wide variation. Thus, the salt-free dyestufi's may be incorporated in any aqueous finish composition in which the salt-containing dyestuffs have previously been used. It is preferred that the concentration of salt-free dyestufi in the aqueous tint finish range from about 0.1 to about 2.5%. based on the weight of the commercial dyes.

In the specific compositions described above, the soap may be of an alkaline metal type or an amine type, for instance potassium, sodium, or triethanolamine oleate or the like, or a mixture of two or more soaps. Furthermore, it may be found advantageous to have present in the comosition an additional emulsifying agent such as sodium alkyl naphthalene sulfonate; an antioxidant or preservative such as sodium-o-phenyl phenate; an emulsion stabilizer, for instance, gelatin or various other ingredients as will readily occur to one skilled in the art. l a 1 While it is generally preferred that aqueous tint finish be applied to the yarn at the time of its initial windup, this invention is not so limited for theaqueous tint finish may be applied to the yarn at any stage in its manufacture before it .is formed into, a fabric. For instance, the

aqueous tint finish may be applied to the yarn as it is being rewound and twisted, or as it is being wound onto -a suitable shipping package. When the aqueous tint finish is applied to the yarn as it is being wound up at the spinning machine, it is best to apply it in accordance with U. 8. Patent No. 1,923,136 in order to secure the greatest possible fugitivity.

While the invention has been described primarily from the viewpoint of fugitively tinting and finishing cellulose acetate yarn, it is also applicable to the tinting and finishing of other cellulose derivative yarns such as cellulose propionate, cellulose butyrate, cellulose aceto-propionate, cellulose aceto-butyrate, benzyl cellulose, ethyl cellulose, and the like.

By means of this invention, finish and color may be uniformly applied to cellulose derivative yarn at any stage in its manufacture due to the much improved stability of the tint finish. Furthermore, when it is desired that the yarn be colored to a deep shade, which requires the use of a. high concentration of dye in the finish, the application can be carried out without any difficulty due to finish instability and with the application of the desired depth of color which may be subsequently removed when desired by a simple boil-off treatment. Not only is the quality of the yarn enhanced by using a tint finish free from inorganic salts according to my invention, but

the amount of waste accumulated from the various textile operations may be reduced as much as 400% as compared with tint finishes made up from ordinary commercial dyes.

A further advantage of my invention is in connection with the finish application to traveling yarn by means of wiper rolls. There is always the necessity of periodic cleaning of the rolls and the finish trough. However, the frequency of finish roll washing in the case of commercial saltcontaining dyestufi in the tint finish as compared with substantially salt-free dyestuff in the tint finish is from five to ten times as often if yarn which is at all acceptable by the trade is to be produced. The matter of washing the finish rolls and the finish trough is not only time-consuming but at each cleaning there is of necessitya certain loss of finish. From tests carried out over an extended period, it has been found that the finish losses when using commercial dyestufi is in the neighborhood of'five times the loss when purified substantially salt-free dyestuflfs are used.

I claim: 1. In the process of fugitive tinting and finish ing of filaments, yarns, and threads of organic derivatives of cellulose wherein a fugitive coloring composition containing a substantial amount of inorganic salt is incorporated in an aqueous finish and the resulting composition is applied to filaments, yarns, and threads of organic derivatives of cellulose, the improvement which comprises adding the coloring composition substantially free of inorganic salts, to the aqueous finish.

2. The method of stabilizing fugitive-colorcontaining aqueous finishes for filaments, yarns, and threads of organic derivatives of cellulose which comprises rendering a fugitive coloringmatter normally-containing substantial amounts of inorganic salts substantially inorganic saltfree, and thereafter incorporating the salt-free coloring matter in the aqueous finish as the color component thereof.

3. An aqueous'finish for filaments, yarns, and threads of organic derivatives of cellulose, said aqueous finish containing in substantially inorganic salt-free condition a fugitive coloring matter for said derivatives, and which coloring matter normally contains substantial amounts of inorganic salts.

4. A stable, aqueous finish for filaments, yarns, and threads of cellulose acetate, said finish containing in substantially inorganic salt-free condition the desired concentration of fugitive coloring matter for cellulose acetate which coloring matter normally contains substantial amounts of.

inorganic salts.

VICTOR L. DENNY, JR. 

